Touch sensor and method of driving the same

ABSTRACT

In an embodiment, a touch sensor may include a sensor part including a first electrode and a second electrode, a signal receiving part, an amplifier circuit part connected between the second electrode and the signal receiving part, an analog-to-digital converter part configured to output a digital signal corresponding to a voltage difference between input terminals, and a processor configured to detect a touch input from the sensor part in response to the digital signal when operating in a first mode, and to output a gain control signal for calibrating a gain value of the amplifier circuit part in response to the digital signal when operating in a second mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/446,717 filed on Jun. 20, 2019, which is acontinuation application of U.S. patent application Ser. No. 15/914,281filed on Mar. 7, 2018, which claims priority under 35 USC § 119 toKorean patent application number 10-2017-0056500, filed on May 2, 2017,the entire disclosures of which are incorporated herein in its entiretyby reference.

BACKGROUND Field

Various exemplary embodiments of the present inventive concept relate toa touch sensor and a method of driving the same.

Description of Related Art

Touch sensor is a type of information input device. It may be used on adisplay device. For example, it may be attached to one surface of adisplay panel implementing image display function or may be implementedin the display panel. A user may input information by pressing ortouching the touch sensor while viewing the images being shown on thedisplay panel.

SUMMARY

Embodiments provide a highly sensitive touch sensor and a method ofdriving the same.

In an embodiment, a touch sensor may include a sensor part including afirst electrode and a second electrode spaced apart from each other, asignal receiving part including a first terminal connected to the firstelectrode and a second terminal connected to the second electrode, anamplifier circuit part connected between the second electrode and thesecond terminal, an analog-to-digital converter part including a thirdterminal connected to another terminal of the signal receiving part anda fourth terminal connected to the second terminal and configured tooutput a digital signal corresponding to a voltage difference betweenthe third and fourth terminals, and a processor configured to detect atouch input from the sensor part in response to the digital signal whenoperating in a first mode, and to output a gain control signal forcalibrating a gain value of the amplifier circuit part in response tothe digital signal when operating in a second mode.

In an embodiment, the signal receiving part may include a firstamplifier including the first and second terminals, a first switchturned on during the first mode and a second switch turned on during thesecond mode, the first and second switches being connected in parallelbetween another terminal of the first amplifier and the first terminal,a first capacitor and a reset switch connected in parallel between thefirst switch and the another terminal of the first amplifier, and asecond capacitor and a first resistor connected in parallel between thesecond switch and the another terminal of the first amplifier.

In an embodiment, the amplifier circuit part may include a secondamplifier including a fifth terminal connected to the second electrodeand a sixth terminal connected to a bias power source and a variableresistor connected between another terminal of the second amplifier andthe bias power source and having a resistance value changing in responseto the gain control signal.

In an embodiment, the second terminal is connected to the variableresistor.

In an embodiment, the touch sensor may further include a peak holdcircuit connected between the another terminal of the signal receivingpart and the peak hold circuit.

In an embodiment, the touch sensor may further include at least oneswitch connected between the peak hold circuit and the third terminaland at least one switch connected between the another terminal of thesignal receiving part and the peak hold circuit.

In an embodiment, the peak hold circuit may include a third amplifierincluding seventh and eighth terminals, the seventh terminal beingconnected to the another terminal of the signal receiving part, at leastone buffer connected between another terminal of the third amplifier andthe third terminal, a first diode connected between the another terminalof the third amplifier and the buffer, a second diode connected betweenthe another terminal of the third amplifier and the eighth terminal inthe same direction as the first diode, and a third capacitor and afourth switch connected in parallel between a connection node betweenthe first diode and the buffer and the second terminal.

In an embodiment, the touch sensor may include at least one switchconnected between the another terminal of the signal receiving part andthe peak hold circuit.

In an embodiment, the analog-to-digital converter part may include adifferential analog-to-digital converter including the third and fourthterminals.

In an embodiment, the analog-to-digital converter part may include afourth amplifier including the third and fourth terminals and ananalog-to-digital converter connected to another terminal of the fourthamplifier.

In an embodiment, the sensor part may include a plurality of firstelectrodes including the first electrode and a plurality of secondelectrodes including the second electrode.

In an embodiment, the first and second electrodes may extend in a firstdirection in an active area provided in the sensor part, and each of thesecond electrodes may include an electrode part surrounded by respectiveone of the first electrodes.

In an embodiment, each of the first electrodes may include a pluralityof electrode cells arranged in the first direction and include at leastone opening disposed inside of each of the plurality of electrode cellsand a plurality of first connecting parts may connect the firstelectrode cells in the first direction.

In an embodiment, each of the second electrodes may include a pluralityof electrode parts disposed inside of each opening of the firstelectrode cells and a plurality of connection lines connecting theelectrode parts in the first direction.

In an embodiment, the touch sensor may include a plurality of signalreceiving parts including the signal receiving part, each of the firstelectrodes being connected to a different one of the signal receivingparts.

In an embodiment, each of the second electrodes may be commonlyconnected to the fifth terminal included in the amplifier circuit part,and a second terminal of the signal receiving part corresponding to eachof the first electrodes may be connected to a different variableresistor among a plurality of variable resistors provided in theamplifier circuit part.

In an embodiment, the touch sensor may further include a plurality ofthird electrodes spaced apart from the first and second electrodes inthe active area and extending in a second direction and a drivingcircuit supplying driving signals to the third electrodes.

In an embodiment, a method of driving a touch sensor including a sensorpart is provided. The touch sensor includes a first electrode and asecond electrode extending in a first direction and spaced apart fromeach other, and a signal receiving part including a first terminal and asecond terminal connected to the first and second electrodes,respectively. The method includes detecting touch input in response to avoltage difference between a sensing signal input to the first terminaland a noise signal input to the second terminal when operating in afirst mode and calibrating a gain value of a second noise signal inresponse to a voltage difference between a first noise signal and thesecond noise signal input to the first and second terminals,respectively, when operating in a second mode.

In an embodiment, the sensor part may further include a third electrodeextending in a second direction and spaced apart from the first andsecond electrodes, and the method further including supplying a drivingsignal to the third electrode when operating in the first mode.

In an embodiment, the touch sensor may further include a variableresistor connected between the second electrode and the second terminal,the method further including generating a gain control signal forcalibrating a resistance value of the variable resistor such that avoltage difference between the first and second noise signals is reducedwhen operating in the second mode.

In an embodiment, a touch sensor may include a sensor part including afirst electrode extending in a first direction, a second electrodeextending in the first direction and electrically disconnected to thefirst electrode, the second electrode including a plurality of electrodeparts and a plurality of connection line connecting adjacent electrodeparts, and a third electrode extending in a second directionsubstantially perpendicular to the first direction and electricallydisconnected to the first electrode and the second electrode.

In an embodiment, the plurality of electrode parts may be disposed inopenings formed in the first electrode.

In an embodiment, the touch sensor may further include a plurality offourth electrodes disposed in the openings to overlap the plurality ofelectrode parts, respectively.

In an embodiment, one of the plurality of fourth electrodes and one ofthe plurality of electrode parts disposed in a same opening may beconnected through a contact hole formed in an insulating layer disposedbetween the plurality of fourth electrodes and the plurality ofelectrode parts.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the example embodiments to those skilled in the art.

In the drawing figures, dimensions may be exaggerated for clarity ofillustration. It will be understood that when an element is referred toas being “between” two elements, it can be the only element between thetwo elements, or one or more intervening elements may also be present.Like reference numerals refer to like elements throughout.

The above and other features and advantages of the present inventiveconcept will become more apparent to those of ordinary skill in the artby describing in detail exemplary embodiments with reference to theattached drawings in which:

FIG. 1 is a schematic view showing a display device according to anembodiment.

FIG. 2 shows a sensor part of a touch sensor according to an embodiment.

FIG. 3 shows a touch sensor according to an embodiment.

FIG. 4 shows a touch sensor according to an embodiment.

FIG. 5 shows an embodiment relating to the sensor part shown in FIG. 4.

FIGS. 6A and 6B show different embodiments of the sensor part shown inFIG. 5.

FIG. 7A show a first layer of the sensor part shown in FIG. 5.

FIG. 7B shows a second layer of the sensor part shown in FIG. 5.

FIG. 8A shows an example of a cross section along line I-I′ in FIG. 5.

FIG. 8B shows an example of a cross section along line II-II′ in FIG. 5.

FIG. 9 shows an embodiment relating to the sensor part shown in FIG. 4.

FIG. 10 shows an embodiment relating to the sensor part shown in FIG. 4.

FIG. 11 shows an embodiment relating to the sensor part shown in FIG. 4.

FIG. 12 shows an embodiment relating to the sensor part shown in FIG. 4.

FIGS. 13 and 14 show a touch sensor according to an embodiment.

FIG. 15 shows an embodiment of an analog-to-digital converter shown inFIGS. 13 and 14.

FIG. 16 shows an embodiment of a peak hold circuit shown in FIGS. 13 and14.

FIG. 17 shows operation of a touch sensor in a first mode according toan embodiment.

FIG. 18 shows operation of a touch sensor in a first mode in anotherembodiment.

FIG. 19 shows operation of a touch sensor in a second mode according toan embodiment.

FIG. 20 shows operation of a touch sensor in a second mode in anotherembodiment.

FIG. 21 shows a touch sensor and operation of the touch sensor in asecond mode according to yet another embodiment.

DETAILED DESCRIPTION

Various exemplary embodiments of the present inventive concept will bedescribed. In the drawings, elements and regions are not drawn to scale,and their sizes and thicknesses may be exaggerated for clarity. In thedescription of the present inventive concept, known configurations thatare not central to the principles of the present inventive concept maybe omitted. Throughout the drawings and corresponding description, thesame components are denoted by the same reference numerals.

In the following detailed description, only certain exemplaryembodiments of the present inventive concept have been shown anddescribed, simply by way of illustration. As those skilled in the artwould realize, the described embodiments may be modified in variousdifferent ways, all without departing from the spirit or scope of thepresent inventive concept. Accordingly, the drawings and description areto be regarded as illustrative in nature and not restrictive. Inaddition, it will be understood that when an element or layer isreferred to as being “on”, “connected to” or “coupled to” anotherelement or layer, it can be directly on, connected or coupled to theother element or layer or intervening elements or layers may be present.In contrast, when an element is referred to as being “directly on,”“directly connected to” or “directly coupled to” another element orlayer, there are no intervening elements or layers present. Like numbersrefer to like elements throughout. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the present inventive concept.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the inventiveconcept. As used herein, the singular forms, “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“includes” and/or “including”, when used in this specification, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this inventive concept belongs. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 is a schematic view showing a display device according to anembodiment. FIG. 2 shows a sensor part of a touch sensor according to anembodiment.

Referring to FIG. 1, a display device according to an embodiment mayinclude a sensor part 100, a touch driver 200, a display panel 300 and adisplay driver 400. The sensor part 100 and the touch driver 200 maymake up a touch sensor.

Although in FIG. 1 the sensor part 100 and the display panel 300 areshown as being separate from each other, it is not limited thereto. Forexample, but not by way of limitation, the sensor part 100 and thedisplay panel 300 may be formed in one body.

In an embodiment, the sensor part 100 may be disposed on at least onearea of the display panel 300. For example, but not by way oflimitation, the sensor part 100 may be disposed on at least one side (orsurface) of the display panel 300 and overlap the display panel 300. Thesensor part 100 may be disposed on one side (for example, on a frontside) in a direction that images are projected. In another embodiment,the sensor part 100 may be directly formed on at least one side orinside of the display panel 300. For example, but not by way oflimitation, the sensor part 100 may be directly formed on an externalside of an upper substrate and/or a lower substrate of the display panel300 (e.g., the upper side of the upper substrate or the lower side ofthe lower substrate) or on an inner side (e.g., the lower side of theupper substrate or the upper side of the lower substrate) of the displaypanel 300.

The sensor part 100 may include an active area 101 capable of sensingtouch input and a non-active area 102 surrounding at least a portion ofthe active area 101. In an embodiment, the active area 101 may bedisposed corresponding to a display area 301 of the display panel 300,and the non-active area 102 may be disposed corresponding to anon-display area 302 of the display panel 300. For example, but not byway of limitation, the active area 101 of the sensor part 100 mayoverlap the display area 301 of the display panel 300, and thenon-active area 102 of the sensor part 100 may overlap the non-displayarea 302 of the display panel 300.

In an embodiment, at least one electrode, for example, but not by way oflimitation, a plurality of sensing electrodes 120 and driving electrodes130, for detecting touch input may be provided in the active area 101.In other words, sensing electrodes 120 and driving electrodes 130 may bedisposed on the display area 301 of the display panel 300. At least aportion of the sensing electrodes 120 and driving electrodes 130 mayoverlap at least one electrode provided in the display panel 300. Forexample, but not by way of limitation, if the display panel 300 is anorganic light emitting display panel or a liquid crystal display panel,the sensing electrodes 120 and driving electrodes 130 may overlap atleast a cathode electrode or a common electrode of the display panel300.

The sensor part 100 may include a plurality of sensing electrodes 120and driving electrodes 130 such that the sensing and driving electrodes120 and 130 cross each other in the active area 101. For example, butnot by way of limitation, there may be a plurality of sensing electrodes120 extending along a first direction and a plurality of drivingelectrodes 130 extending along a second direction to cross the sensingelectrodes 120 in the active area 101. In an embodiment, the sensingelectrodes 120 and the driving electrodes 130 may be insulated from eachother by at least one insulating layer which is not shown.

A capacitance Cse may be formed between the sensing electrodes 120 andthe driving electrodes 130, particularly at a cross section thereof. Thecapacitance Cse may change when there is a touch input at acorresponding point or at a periphery thereof. Accordingly, touch inputmay be sensed by detecting change in the capacitance Cse.

The shape, size, arrangement direction, etc. of the sensing electrodes120 and the driving electrodes 130 are not limited. In an embodimentrelated thereto, but not by way of limitation, the sensing electrodes120 and the driving electrodes 130 may be configured as shown in FIG. 2.Although in FIGS. 1 and 2, a mutual capacitive touch sensor is shown asa touch sensor, but the touch sensor in an embodiment is not limitedonly to a mutual capacitive touch sensor.

Referring to FIG. 2, the sensor part 100 may include a base substrate110 having an active area 101 and a non-active area 102, a plurality ofsensing electrodes 120 and driving electrodes 130 disposed on the activearea 101 on the base substrate 110, and a plurality of wires 140 and apad part 150 disposed on the non-active area 102 on the base substrate110. In another embodiment, if the touch sensor is a self-capacitivetouch sensor, there may be a plurality of sensor electrodes distributedin the active area 101 which receive driving signal during one period ofa touch driving period and output sensing signal during another period.

The base substrate 110 may be a substrate that becomes a base for thesensor part 100, and it may be a rigid substrate or a flexiblesubstrate. For example, but not by way of limitation, the base substrate110 may be a rigid substrate that is made of glass or reinforced glassor a flexible substrate that is made of a thin film of pliant plasticmaterial. In an embodiment, the base substrate 110 may be one of thesubstrates that form the display panel 300. For example, but not by wayof limitation, in an embodiment where the sensor part 100 and thedisplay panel 300 are integrated in one body, the base substrate 110 maybe at least one substrate (e.g., an upper substrate) that makes up thedisplay panel 300 or a thin film encapsulation TFE.

The sensing electrodes 120 may extend along a first direction, forexample, but not by way of limitation, along an X direction. In anembodiment, each of the sensing electrodes 120 in each row may include aplurality of first electrode cells 122 arranged along a first directionand first connecting parts 124 physically and/or electrically connectingthe first electrode cells 122 of each row along the first direction. Inan embodiment, the first connecting parts 124 may be formed as one bodywith the first electrode cells 122 or as a connection pattern as abridge or in a bridge shape. In FIG. 2, the first connecting parts 124are shown in an embodiment as being arranged in the first direction, butthey are not limited thereto. For example, in another embodiment, thefirst connecting parts 124 may be arranged in a direction of a diagonalline that is inclined toward the first direction. In FIG. 2, the firstconnecting parts 124 are shown as having a straight shape (or a barshape), but they are not limited thereto. For example, but not by way oflimitation, the first connecting part 124 may have a shape in which atleast one area is bent or flexed. In FIG. 2, two adjacent firstelectrode cells 122 are shown as being connected to each other throughone first connecting part 124 disposed therebetween, but they are notlimited thereto. For example, but not by way of limitation, in anotherembodiment, two adjacent first electrode cells 122 may be connected toeach other through a plurality of first connecting parts 124 disposedtherebetween.

In an embodiment, the first electrode cells 122 and/or the firstconnecting parts 124 may include at least one of metal material,transparent conductive material and other various conductive materials,thus having conductivity. For example, but not by way of limitation, thefirst electrode cells 122 and/or the first connecting parts 124 mayinclude at least one of various metal materials including gold (Au),silver (Ag), aluminum (Al), molybdenum (Mo), chrome (Cr), titanium (Ti),nickel (Ni), neodymium (Nd), copper (Cu), platinum (Pt), etc., or analloy thereof. Also, the first electrode cells 122 and/or the firstconnecting parts 124 may include at least one of silver (Ag), silvernanowire (AgNW), indium tin oxide (ITO), indium zinc oxide (IZO),antimony zinc oxide (AZO), indium tin zinc oxide (ITZO), zinc oxide(ZnO) and various transparent conductive materials including tin oxide(SnO2), carbon nano tube, graphene, etc. In addition, the firstelectrode cells 122 and/or the first connecting parts 124 may include atleast one of various conductive materials capable of providingconductivity. In an embodiment, each of the first electrode cells 122and/or the first connecting parts 124 may be a single layer or multilayers.

In an embodiment, if the touch sensor is a mutual capacitive touchsensor, the sensing electrodes 120 may output sensing signal in responseto driving signal input to the driving electrodes 130. For example, butnot by way of limitation, the sensing electrodes 120 may be Rxelectrodes outputting sensing signal corresponding to touch input.

The driving electrodes 130 may extend along a second direction, forexample but not by way of limitation, along a Y direction. In anembodiment, each of the driving electrodes 130 disposed in each columnmay include a plurality of second electrode cells 132 arranged along thesecond direction and second connecting parts 134 physically and/orelectrically connecting the second electrode cells 132 of each columnalong the second direction. In an embodiment, the second connectingparts 134 may be formed as one body with the second electrode cells 132or as a connection pattern as a bridge or in a bridge shape. In FIG. 2,the second connecting parts 134 are shown in an embodiment as beingarranged in the second direction, but they are not limited thereto. Forexample, in another embodiment, the second connecting parts 134 may bearranged in a direction of a diagonal line that is inclined toward thesecond direction. In FIG. 2, the second connecting parts 134 are shownas having a straight shape (or a bar shape), but they are not limitedthereto. For example, but not by way of limitation, the secondconnecting part 134 may have a shape in which at least one area is bentor flexed. In FIG. 2, two adjacent second electrode cells 132 are shownas being connected to each other through one second connecting part 134disposed therebetween, but they are not limited thereto. For example,but not by way of limitation, in another embodiment, two adjacent secondelectrode cells 132 may be connected to each other through a pluralityof second connecting parts 134 disposed therebetween.

In an embodiment, the second electrode cells 132 and/or the secondconnecting parts 134 may include at least one of metal material,transparent conductive material and other various conductive materials,thus having conductivity. For example, but not by way of limitation, thesecond electrode cells 132 and/or the second connecting parts 134 mayinclude at least one of the conductive materials mentioned above as thematerials making up the first electrode cells 122 and/or the firstconnecting parts 124. In addition, the second electrode cells 132 and/orthe second connecting parts 134 may be formed of the same material asthe materials making up the first electrode cells 122 and/or the firstconnecting parts 124, or different material. In addition, each of thesecond electrode cells 132 and/or the second connecting parts 134 may bea single layer or multi layers.

In an embodiment, if the touch sensor is a mutual capacitive touchsensor, the driving electrodes 130 may receive a predetermined drivingsignal for driving the touch sensor. For example, but not by way oflimitation, if the touch sensor in an embodiment is a mutual capacitivetouch sensor, the driving electrodes 130 may be Tx electrodes receivingdriving signal during a period when the touch sensor is activated.

In FIG. 2, the first and second electrode cells 122 and 132 are shown tohave a diamond shape. However, the shapes, sizes, etc. of the first andsecond electrode cells 122 and 132 may vary. For example, but not by wayof limitation, the first and second electrode cells 122 and 132 may haveother shapes such as circular, hexagonal, etc.

In FIG. 2, each of the sensing electrodes 120 and the driving electrodes130 is shown to be formed of a plurality of electrode cells 122 or 132and the connecting parts 124 or 134. However, the shapes of the sensingelectrodes 120 and/or driving electrodes 130 may vary. For example, butnot by way of limitation, in another embodiment, the sensing electrodes120 and the driving electrodes 130 may be implemented with rectangularbar type electrode extending along a first direction and a seconddirection, respectively.

In an embodiment, in the non-active area 102, there may be wires 140 forelectrically connecting the sensing electrodes 120 and the drivingelectrodes 130 disposed in the active area 101 to a touch driver 200,etc. In an embodiment, the wires 140 may include first wires 142 forelectrically connecting each sensing electrode 120 to the pad part 150and second wires 144 for electrically connecting each driving electrode130 to the pad part 150. For example, but not by means of limitation,each wire 140 may electrically connect any one of the sensing electrodes120 and the driving electrodes 130 to a predetermined pad 152 providedto the pad part 150. In FIG. 2, for convenience of illustration, it isshown that the first wires 142 and the second wires 144 are connectedonly on one end of the sensing electrodes 120 and the driving electrodes130, respectively, but a connection structure between the sensingelectrodes 120 and the driving electrodes 130 and the first and secondwires 142 and 144 may change. For example, but not by way of limitation,in another embodiment, at least one of the first wires 142 and thesecond wires 144 may be connected to both ends of the sensing electrodes120 or the driving electrodes 130.

The pad part 150 may include many pads 152 for electrically connectingthe sensing electrodes 120 and the driving electrodes 130 to an externaldriving circuit, for example, but not by way of limitation, the touchdriver 200. The sensor part 100 and the touch driver 200 may communicateto each other through the pad part 150.

Referring to FIG. 1, the touch driver 200 may be electrically connectedto the sensor part 100 and transmit/receive signal needed for drivingthe sensor part 100. For example, but not by way of limitation, thetouch driver 200 may detect touch input by receiving a sensing signal inresponse to a driving signal from the sensor part 100 after supplyingthe driving signal to the sensor part 100. The touch driver 200 mayinclude a driving circuit and a sensing circuit. In an embodiment, thedriving circuit and the sensing circuit may be integrated into a touchIC T-IC in the touch driver 200 but they are not limited thereto.

In an embodiment, the driving circuit may be electrically connected tothe driving electrodes 130 of the sensor part 100 and sequentiallysupply driving signals to the driving electrodes 130. In an embodiment,the sensing circuit may be electrically connected to the sensingelectrodes 120 of the sensor part 100, receive sensing signal from thesensing electrodes 120 and detect touch input by performing signalprocessing.

The display panel 300 may include the display area 301 and thenon-display area 302 surrounding at least one area of the display area301. A plurality of scan lines 310 and data lines 320, and a pluralityof pixels P connected to the scan lines 310 and the data lines 320 maybe provided in the display area 301. Various driving signal for drivingthe pixels P and/or wires for supplying driving power may be provided inthe non-display area 302.

The type of display panel 300 is not limited. For example, but not byway of imitation, the display panel 300 may be a self-luminescencedisplay panel such as an organic light emitting display panel. Thedisplay panel 300 may be a non self-emissive display panel such as aliquid crystal display panel, an electro-phoretic display panel and anelectro-wetting display panel. If the display panel 300 is anon-self-emissive display panel, the display device may further includea back-light unit for supplying light to the display panel 300.

The display driver 400 may be electrically connected to the displaypanel 300 and supply signal needed for driving the display panel 300.For example, but not by way of limitation, the display driver 400 mayinclude at least one of a scan driver supplying scan signal to the scanlines 310, a data driver supplying data signal to the data lines 320,and a timing controller for driving the scan driver and the data driver.In an embodiment, the scan driver, the data driver and/or the timingcontroller may be integrated into one display IC D-IC, but they are notlimited thereto. For example, but not by way of limitation, in anotherembodiment, at least one of the scan driver, the data driver and atiming controller may be integrated or mounted on the display panel 300.

FIG. 3 shows a touch sensor according to an embodiment. For convenience,in FIG. 3, one sensing electrode 120 and one driving electrode 130 ofsensing electrodes 120 and driving electrodes 130 provided in the sensorpart 100 and capacitance Cse formed at a cross section thereof areshown. In FIG. 3, a driving circuit 210 and a sensing circuit 220 whichis focused on the sensing electrode 120 and the driving electrode 130forming the capacitance Cse are shown.

Referring to FIG. 3, the sensor part 100 may include the at least a pairof the sensing electrode 120 and the driving electrode 130 which form acapacitance Cse. The driving electrode 130 may be electrically connectedto the driving circuit 210 of a touch driver 200, and the sensingelectrode 120 may be electrically connected to a sensing circuit 220 ofthe touch driver 200. For convenience, in FIG. 3, the driving circuit210 and the sensing circuit 220 are drawn as separated from each other,but they are not limited thereto. For example, but not by way oflimitation, the driving circuit 210 and the sensing circuit 220 may beseparated from each other, or at least a portion of the driving circuit210 and the sensing circuit 220 may be integrated in one body.

A method of driving the touch sensor may include supplying a drivingsignal Sdr to a driving electrode 130 from the driving circuit 210. Ifthe sensor part 100 includes a plurality of driving electrodes 130 asshown in FIGS. 1 and 2, the driving circuit 210 may supply the drivingsignals Sdr to the driving electrodes 130 sequentially. A sensing signalSse in response to the driving signal Sdr applied to each drivingelectrode 130 may be output from each sensing electrode 120 due to acoupling effect of the capacitance Cse in the sensor part 100. Thesensing signal Sse may be input to the sensing circuit 220 of the touchdriver 200. If the sensor part 100 includes a plurality of sensingelectrodes 120 as shown in FIGS. 1 and 2, the sensing circuit 220 mayinclude a plurality of sensing channels electrically connected to eachsensing electrode 120 (hereinafter, referred to as “Rx channels”).Sensing signal outputs from the plurality of sensing electrodes 120 maybe received through the Rx channels. In an embodiment, each of the Rxchannels may include at least a signal receiving part 221.

The sensing circuit 220 may amplify, convert and process the sensingsignal Sse input from each sensing electrode 120 through the Rx channeland detect the touch input accordingly. The sensing circuit 220 mayinclude a signal receiving part 221, an analog-to-digital converter part223 and a processor 225.

The signal receiving part 221 may receive sensing signal Sse from eachsensing electrode 120 through the Rx channel. In an embodiment, thetouch sensor may include a plurality of signal receiving parts 221connected to each of the plurality of sensing electrodes 120 through theRx channel. The signal receiving part 221 may be included in each of theRx channels.

The signal receiving part 221 may amplify and output an amplifiedsensing signal Sse to the ADC 223. For example, but not by way oflimitation, the signal receiving part 221 may be implemented with ananalog front end (AFE) that includes a first amplifier AMP1. In anembodiment, the first amplifier AMP1 may be an operational amplifier. Inan embodiment, a first input terminal (or a first terminal) IN1 of thesignal receiving part 221, e.g., an inverting input terminal of thefirst amplifier AMP1 may be electrically connected to the sensingelectrode 120 of the applicable Rx channel. That is, the sensing signalSse from the sensing electrode 120 may be input to the first inputterminal IN1 of the first amplifier AMP1. A first capacitor C1 and areset switch SWr may be connected in parallel between the first inputterminal IN1 and the output terminal OUT of the first amplifier AMP1.Meanwhile, a second input terminal (or a second terminal) IN2 of thesignal receiving part 221, e.g., a non-inverting input terminal of thefirst amplifier AMP1, is a reference terminal and may be electricallyconnected to, for example, but not by way of limitation, a ground GNDpower.

The analog-to-digital converter part 223 may convert an analog signalinput from the signal receiving part 221 into a digital signal. In anembodiment, the analog-to-digital converter parts 223 may be provided asmany as the number of the sensing electrodes 120 to correspond to eachRx channel corresponding to each sensing electrode 120 at a ratio of1:1. In another embodiment, a plurality of Rx channels corresponding toa plurality of sensing electrodes 120 may be configured to share oneanalog-to-digital converter part 223. A switching circuit for channelselection may be additionally provided between each of the signalreceiving parts 221 and the analog-to-digital converter parts 223.

A processor 225 may perform signal processing on the digital signalconverted by the analog-to-digital converter part 223 and detect a touchinput according to the signal processing result. For example, but not byway of limitation, the processor 225 may detect whether there is anoccurrence of a touch input and a position thereof by comprehensivelyanalyzing a sensing signal input, that is, the sensing signal Sse thatis amplified and digital converted, via the signal receiving part 221and the analog-to-digital converter part 223 from a plurality of sensingelectrodes 120. In an embodiment, the processor 225 may be implementedwith a micro processor MPU. A memory that is needed for driving theprocessor 225 may be additionally provided in the sensing circuit 220.However, the configuration of the processor 225 is not limited thereto.For example, but not by way of limitation, the memory may be integratedinto a microcontroller MCU, etc.

The touch sensor described above may be combined with a display panel300, etc. For example, but not by way of limitation, the sensor part 100of the touch sensor may be manufactured in one body with the displaypanel 300 or may be manufactured separately from the display panel 300and the separately manufactured sensor part 100 of the touch sensor maybe combined with at least one side of the display panel 300.

As such, if the sensor part 100 and the display panel 300 are combinedtogether, a parasitic capacitance may occur between the sensor part 100and the display panel 300. Due to the coupling effect of the parasiticcapacitance, the noise from the display panel 300 may be transmitted tothe touch sensor, particularly the sensor part 100. For example, but notby way of limitation, the noise due to the display driving signal usedfor driving the display panel 300 may affect the sensor part 100. Forexample, but not by way of limitation, the sensing electrodes 120 andthe driving electrodes 130 may overlap the cathode electrode or thecommon electrode. Display noise (common mode noise) due to the displaydriving signal applied to the cathode electrode or the common electrodemay affect the sensor part 100.

The noise from the display panel 300 may cause ripple of sensing signalSse, and thus sensitivity of the touch sensor may decrease as a result.Various embodiments capable of enhancing sensitivity of touch sensorwill be described subsequently.

FIG. 4 shows a touch sensor according to an embodiment. For convenience,the base substrate, the pad part, etc. shown in FIG. 2 are omitted inFIG. 4, the sensor part in FIG. 4 may be implemented on the basesubstrate. In FIG. 4, same reference numerals are used with respect tothe similar or same components, and detailed description thereof isomitted.

Referring to FIG. 4, in an embodiment, the touch sensor may include asensor part 100, a driving circuit 210 and a sensing circuit 220electrically connected to the sensor part 100. In an embodiment, thesensor part 100 may further include a plurality of noise detectingelectrodes 160 extending in the same direction as the sensing electrodes120 such that they will make pairs with the sensing electrodes 120.

The sensor part 100 may include at least a pair of a sensing electrode(first electrode) 120 and a noise detecting electrode (second electrode)160. The sensing electrode 120 and the noise detecting electrode 160 arespaced apart from each other. The sensor part 100 may further include atleast one driving electrode (third electrode) 130 crossing the pair ofsensing electrode 120 and noise detecting electrode 160.

For example, but not by way of limitation, the sensor part 100 mayinclude a plurality of sensing electrodes (first electrodes) 120 and aplurality of noise detecting electrodes (second electrodes) 160 makingpairs with the sensing electrodes 120. The sensor part 100 may include aplurality of driving electrodes (third electrodes) 130 crossing thesensing electrodes 120 and the noise detecting electrodes 160.

At least a portion of the sensing electrodes 120, the driving electrodes130 and the noise detecting electrodes 160 may have an area thatoverlaps and/or crosses each other, but they may be insulated from oneanother with insulating layers (not shown) disposed therebetween. Thatis, the sensing electrodes 120, the driving electrodes 130 and the noisedetecting electrodes 160 may be distanced apart and electricallyinsulated from each other, and a capacitance may be formed therebetween.

In an embodiment, the sensing electrodes 120 may extend along a firstdirection in an active area 101, and the driving electrodes 130 mayextend along a second direction in the active area 101 to cross thesensing electrodes 120. The noise detecting electrodes 160 may extendalong the first direction in the active area 101 as the sensingelectrodes 120, and an area of the noise detecting electrodes 160 mayoverlap the sensing electrodes 120.

In an embodiment, each of the sensing electrodes 120 may include aplurality of first electrode cells 122 and a plurality of connectingparts 124 connecting the first electrode cells 122 along the firstdirection. For example, but not by way of limitation, each of thesensing electrodes 120 may include a plurality of first electrode cells122 arranged along the first direction. The first electrode cells 122arranged in each row line (or column line) may be connected along thefirst direction by the first connecting parts 124. Meanwhile, the shapesof the sensing electrodes 120 are not limited thereto. For example, butnot by way of limitation, each of the sensing electrodes 120 may beimplemented as a one-body bar type electrode.

In an embodiment, each of the first electrode cells 122 may include atleast one opening (or a hole) inside of it. For example, but not by wayof limitation, each of the first electrode cells 122 may have a centralopen part.

In an embodiment, in the opening of each of the first electrode cells122, there may be a first dummy pattern 126 that is spaced apart fromthe each of the first electrode cells 122. In an embodiment, the firstdummy patterns 126 and the first electrode cells 122 may be formed ofthe same material and may be formed on the same layer, but they are notlimited thereto.

Meanwhile, the first dummy patterns 126 should not be understood to belimiting. For example, but not by way of limitation, no opening may beformed inside each first electrode cell 122, or the first dummy patterns126 may be omitted.

In an embodiment, an electrode part 162 of the noise detecting electrode160 may be disposed inside each sensing electrode 120. For example, butnot by way of limitation, each of the electrode parts 162 of the noisedetecting electrodes 160 may be surrounded by respective one of thesensing electrodes 120. The each of the electrode parts 162 of the noisedetecting electrodes 160 may be completely surrounded by respective oneof the sensing electrodes 120.

In an embodiment, each of the noise detecting electrodes 160 may includea plurality of electrode parts 162 arranged along the first direction.In an embodiment, each of the electrode parts 162 may be spaced apartfrom the first electrode cells 122 and physically not connected to thefirst electrode cells 122. For example, but not by way of limitation,each of the electrode parts 162 may be positioned to overlap each of thefirst dummy patterns 126 in the opening provided inside each of thefirst electrode cells 122.

In an embodiment, each of the electrode parts 162 may have the same areaas, or a different area from, the corresponding first dummy pattern 126.For example, but not by way of limitation, a pair of electrode part 162and first dummy pattern 126 that overlap each other may have the samearea as each other and completely overlap each other. In FIG. 4, inorder to clearly distinguish the electrode part 162 from the first dummypattern 126, the embodiment shows that they have different areas fromeach other, for example, each of the electrode parts 162 has a smallerarea than each of the first dummy patterns 126 and is provided insidethe area where the first dummy pattern 126 is provided.

The electrode parts 162 disposed on the same row (or column) along thefirst direction may form noise detecting electrodes 160 by beingelectrically connected along the first direction through connectionlines 164. Each of the noise detecting electrodes 160 may include aplurality of electrode parts 162 surrounded by each of the firstelectrode cells 122 and a plurality of connection lines 164 physicallyand/or electrically connecting the electrode parts 162 along the firstdirection.

In an embodiment, the electrode parts 162 and/or the connection lines164 may include at least one of a metal material, a transparentconductive material and other various conductive materials, therebyhaving conductivity. For example, but not by way of limitation, theelectrode parts 162 and/or the connection lines 164 may include at leastone of the conductive materials mentioned above as materials for formingthe first electrode cells 122, the first connecting parts 124, thesecond electrode cells 132 and/or the second connecting part 134. Theelectrode parts 162 and/or the connection lines 164 may be formed of thesame materials as, or different materials from, the first electrodecells 122, the first connecting parts 124, the second electrode cells132 and/or the second connecting parts 134. Each of the electrode parts162 and/or the connection lines 164 may be a single layer or multilayers.

In an embodiment, each of the noise detecting electrodes 160 may beelectrically connected to the sensing circuit 220 via each third wire146. In an embodiment, a buffer BU may be disposed between each of thenoise detecting electrodes 160 and the corresponding signal receivingpart 221. The buffer BU may be electrically connected between the noisedetecting electrode 160 and the signal receiving part 221 thatcorrespond to each other, buffer the signal input from the noisedetecting electrode 160 (e.g., a noise signal Sno) and output it to thesignal receiving part 221 in the sensing circuit 220. In an embodiment,the inverting input terminal of the buffer BU may be electricallyconnected to the output terminal of the buffer BU, and the non-invertinginput terminal of the buffer BU may be electrically connected to thecorresponding noise detecting electrode 160 and receive the noise signalSno.

In an embodiment, a sensing electrode 120 and a noise detectingelectrode 160 disposed in an area that correspond to each other amongthe sensing electrodes 120 and the noise detecting electrodes 160 maymake a pair. For example, but not by way of limitation, the sensingelectrode 120 disposed in the first row of the active area 101 and thenoise detecting electrode 160 disposed in the first row that includesthe electrode part 162 disposed in the opening inside the sensingelectrode 120 may make a pair.

In an embodiment, a pair of sensing electrode 120 and noise detectingelectrode 160 may have at least one overlapping area. For example, butnot by way of limitation, the connection lines 164 electricallyconnecting a plurality of electrode parts 162 may overlap the firstelectrode cells 122. The connection lines 164 may be disposed on a layerthat is different from the layer on which the first electrode cells 122are disposed. Consequently, the sensing electrodes 120 and the noisedetecting electrodes 160 may be electrically insulated from each other.

The first connecting parts 124 may be connected in one body with thefirst electrode cells 122 on the same layer as the first electrode cells122 or may be disposed on a layer different from the layer on which thefirst electrode cells 122 are disposed and electrically connected to thefirst electrode cells 122 via contact holes. For example, but not by wayof limitation, the first connecting parts 124 may be provided on thesame layer as the electrode parts 162 and/or the connection lines 164but not overlap the electrode parts 162 and/or the connection lines 164.

In an embodiment, the second electrode cells 132 may include at leastone opening (or hole) inside of it as is the case with the firstelectrode cells 122. For example, but not by way of limitation, thesecond electrode cells 132 may have an opening at a center.

Also, in an embodiment, inside the openings of the second electrodecells 132, there may be provided second dummy patterns 136 that arespaced apart from the second electrode cells 132. For example, but notby way of limitation, inside the openings of the second electrode cells132, there may be provided second dummy patterns 136 that are spacedapart from the second electrode cells 132 on the same layer as thesecond electrode cells 132. In an embodiment, the second dummy patterns136 may be formed of the same materials as the second electrode cells132, but they are not limited thereto.

As such, if the driving electrodes 130 have a similar structure and/orshape to the sensing electrodes 120, uniform viewing (or visual)characteristics may be secured throughout in the active area 101.However, it is not limited thereto. For example, but not by way oflimitation, no opening may be formed inside the second electrode cells132, or second dummy patterns 136 may be omitted.

Meanwhile, FIG. 4 shows that the sensing electrodes 120, the drivingelectrodes 130 and the noise detecting electrodes 160 includingelectrode cells 122 and 132 or electrode parts 162 that are boardshaped, however, they are not limited thereto. For example, but not byway of limitation, in another embodiment, at least one of the sensingelectrodes 120, the driving electrodes 130 and the noise detectingelectrodes 160 may be electrodes having mesh shape.

The driving circuit 210 may be electrically connected to the drivingelectrodes 130 and may supply the driving signals Sdr to the drivingelectrodes 130. For example, but not by way of limitation, the drivingcircuit 210 may supply the driving signals Sdr sequentially to thedriving electrodes 130 during a period where the touch sensor isactivated. In an embodiment, the driving signals Sdr may be an alternatecurrent signal having a predetermined cycle as a pulse wave.

The sensing circuit 220 may include a plurality of signal receivingparts 221 receiving sensing signal Sse1 from each of the sensingelectrodes 120, a plurality of analog-to-digital converter parts 223electrically connected to each output terminal of the signal receivingparts 221, and a processor 225 detecting touch input by receivingsignals digitally converted from the analog-to-digital converter parts223. The signal receiving part 221, the analog-to-digital converter part223 and the processor 225 have been described with reference toembodiment of FIG. 3 above so detailed description will be omitted.

In an embodiment in FIG. 4, first and second input terminals IN1 and IN2of the signal receiving parts 221 may be electrically connected to arespective sensing electrode 120 and a respective noise detectingelectrode 160. For example, but not by way of limitation, the firstinput terminal IN1 of the first signal receiving part 221 that receivesthe sensing signal Sse1 from the sensing electrode 120 positioned in thefirst row of the active area 101 may be electrically connected to thesensing electrode 120 of the first row, and the second input terminalIN2 of the first signal receiving part 221 may be electrically connectedto the noise detecting electrode 160 of the first row. In an embodiment,each of the signal receiving parts 221 may include a first amplifierAMP1 including first and second input terminals IN1 and IN2, and thesecond input terminal IN2 may be a reference terminal (or a groundterminal) of the signal receiving part 221 (e.g., AFE). Each of thesignal receiving parts 221 may output signal corresponding to a voltagedifference of the first and second input terminals IN1 and IN2.

As described above, in an embodiment, electrodes for detecting touchinput, for example, in addition to the sensing electrodes 120 and 130,noise detecting electrodes 160 may be additionally included. The noisedetecting electrodes 160 may be insulated from the sensing electrodes120 and the driving electrodes 130. Therefore, there may be acapacitance formed between the sensing electrodes 120, the drivingelectrodes 130 and/or the noise detecting electrodes 160.

The noise detecting electrodes 160 may be electrically connected to thesecond input terminal of each signal receiving part 221. Therefore,reference voltage of the signal receiving parts 221 may change alongwith the voltage change of the noise detecting electrodes 160. That is,according to the potential (voltage level) of the noise detectingelectrodes 160, the reference potential of the signal receiving parts221 may change.

The potential of the noise detecting electrodes 160 may change dependingon the noise from the display panel 300, etc. For example, but not byway of limitation, the potential of the noise detecting electrodes 160may change in response to a common mode noise from the display panel300, etc.

Therefore, in an embodiment, there may be more noise detectingelectrodes 160 provided to the active area 101, and if a referencepotential of the signal receiving parts 221 changes using output signalfrom the noise detecting electrodes 160, the common mode noise may beoffset. A pair of sensing electrode 120 and noise detecting electrode160 may have ripple that corresponds to each other in response to thecommon mode noise. In particular, in an embodiment, a pair of sensingelectrode 120 and noise detecting electrode 160 may extend in the samedirection and may be disposed in substantially same locations in theactive area 101, and therefore, they may receive the same noise or noisethat has very similar shape and/or size. Each of the noise detectingelectrodes 160 may be electrically connected to a different signalreceiving part 221 via a different third wire 146. In other words, thesecond input terminal IN2 of the signal receiving part 221 where thefirst input terminal IN1 is connected to a predetermined sensingelectrode 120 may be electrically connected to the noise detectingelectrode 160 forming a pair with the sensing electrode 120 via apredetermined third wire 146.

As such, if the first and second input terminals IN1 and IN2 of thesignal receiving part 221 are electrically connected to thecorresponding sensing electrode 120 and noise detecting electrode 160,the noise component (ripple) included in the sensing signal Sse1 fromthe sensing electrode 120 may be offset inside the signal receiving part221. Accordingly, the signal receiving part 221 may output sensingsignal Sse2 from which noise is removed (or reduced).

In an embodiment, the electrode parts 162 of the noise detectingelectrodes 160 may be arranged inside (or surrounded by) the sensingelectrodes 120, respectively. As a result, enough distance between thedriving electrodes 130 for receiving driving signal Sdr and the noisedetecting electrodes 160 for receiving noise signal Sno may be secured.Accordingly, by reducing or preventing voltage change of the noisedetecting electrodes 160 due to the driving signal Sdr, noise signal Snomay be effectively detected.

In an embodiment, the signal-to-noise ratio (SNR) of the touch sensormay be increased to enhance sensitivity. In an embodiment, a touchsensor of high sensitivity and a display device having the same may beprovided.

An embodiment may be effectively applied to a display device having ashort distance between the sensor part 100 and the display panel 300,etc. For example, but not by way of limitation, an embodiment may beeffectively applied to enhance touch sensitivity in a display devicehaving an on-cell type which is sensitive to noise as the sensingelectrodes 120 and the driving electrodes 130 are directly formed on theupper substrate or the thin film encapsulation layer of the displaypanel 300, etc. However, it is not limited thereto, and it should beunderstood that an embodiment can be applied to various types of displaydevice or electronic device.

FIG. 5 shows an embodiment relating to the sensor part shown in FIG. 4.FIGS. 6A and 6B show different embodiments of the sensor part shown inFIG. 5. FIG. 7A show a first layer of the sensor part shown in FIG. 5.FIG. 7B shows a second layer of the sensor part shown in FIG. 5. FIG. 8Ashows an example of a cross section along line I-I′ in FIG. 5. FIG. 8Bshows an example of a cross section along line II-II′ in FIG. 5. InFIGS. 5 to 8B, same reference numerals are used for similar or samecomponents as found in FIG. 4, and detailed description thereof will beomitted.

Referring to FIGS. 5 to 8B, in an embodiment, first electrode cells 122and second electrode cells 132 may be arranged on the same layer. Forexample, but not by way of limitation, the first electrode cells 122 andthe second electrode cells 132 may be provided as a first layer L1 on asubstrate 110. One of first connecting parts 124 and second connectingparts 134 may be disposed as the first layer L1 along with the first andsecond electrode cells 122 and 132 on the substrate 110. For example,but not by way of limitation, the second connecting parts 134 may beprovided as the first layer L1 and the second electrode cells 132 areconnected one another by the second connecting parts 134 which areformed of the same material and formed through a same process as thesecond electrode cells 132. However, they are not limited thereto. Inanother embodiment, all of first and second connecting parts 124 and 134may be disposed on a layer that is different from the first and secondelectrode cells 122 and 132. In yet another embodiment, first and secondelectrode cells 122 and 132 may be disposed on different layers. Forexample, but not by way of limitation, the first electrode cells 122 maybe connected to the first connecting parts 124 in one body, the secondelectrode cells 132 may be connected to the second connecting parts 134in one body, and the sensing electrodes 120 and the driving electrodes130 may be disposed on different layers with at least one insulatinglayer (or a space) interposed therebetween.

In an embodiment, the first connecting parts 124 may be disposed as asecond layer L2 that is disposed on the first layer L1 with at least oneinsulating layer, e.g., a first insulating layer 170 interposed betweenthe first connecting part 124 and the first layer L1. In an embodiment,the second layer L2 may be disposed between the substrate 110 and thefirst layer L1. In other words, the first connecting parts 124 may beimplemented as a lower bridge as shown in FIGS. 8A and 8B. However, theyare not limited thereto. For example, but not by way of limitation, inanother embodiment, the positions of the first layer L1 and the secondlayer L2 may be interchangeable. In other words, depending onembodiment, the first layer L1 may be disposed between the substrate 110and the second layer L2, and the first connecting parts 124 may beimplemented as the upper bridge. As such, if the first connecting parts124 are disposed on different layer from the first electrode cells 122,the first connecting parts 124 may be electrically connected betweenadjacent first electrode cells 122 via a first contact holes CH1.Meanwhile, in yet another embodiment, the first connecting parts 124 andthe noise detecting electrodes 160 may be disposed on different layers.For example, but not by way of limitation, the sensing electrodes 120and the driving electrodes 130 may be disposed on different layers thatare spaced apart, and the noise detecting electrodes 160 may be arrangedon a middle layer which is disposed between the sensing electrodes 120and the driving electrodes 130 with insulating layers disposed above andbelow the noise detecting electrodes 160.

In an embodiment, inside the first electrode cells 122, e.g., at acentral part, an opening OP may be formed, and first dummy patterns 126may be arranged to be spaced apart from the first electrode cells 122inside the opening OP. Also, inside the second electrode cells 132,e.g., at a central part, an opening OP may be formed, and second dummypatterns 136 may be arranged to be spaced apart from the secondelectrode cells 132 inside the opening OP. In an embodiment, the firstand second dummy patterns 126 and 136 may be provided as the first layerL1 of the sensor part 100 along with the first and second electrodecells 122 and 132. However, they are not limited thereto. For example,but not by way of limitation, in another embodiment, at least one of thefirst and second dummy patterns 126 and 136 may be omitted or providedon different layers from the first and second electrode cells 122 and132.

In an embodiment, electrode parts 162 that are spaced apart from thefirst electrode cells 122 may be arranged inside the first electrodecells 122. For example, but not by way of limitation, the electrodeparts 162 may be provided as the second layer L2. In an embodiment, inorder to reduce parasitic capacitance between the sensing electrodes 120and the driving electrodes 130 and the noise detecting electrodes 160,the electrode parts 162 may be arranged such that they would not overlapthe first electrode cells 122. For example, but not by way oflimitation, the electrode parts 162 may have a smaller area than thefirst dummy patterns 126 yet overlap the first dummy patterns 126 asshown in FIG. 5. For example, but not by way of limitation, theelectrode parts 162 may be disposed at a central part of the secondelectrode cells 122 to be surrounded by the second electrode cells 122.

However, they are not limited thereto, and the electrode parts 162 mayhave various areas, shapes and/or positions. For example, but not by wayof limitation, a pair of electrode part 162 and first dummy pattern 126corresponding to each other may have same area and shape and yetcompletely overlap each other as shown in FIG. 6A.

In an embodiment, in FIGS. 5 and 6A, the first and second electrodecells 122 and 132, the first and second connecting parts 124 and 134,the first and second dummy patterns 126 and 136 and the electrode parts162 are shown to be board-shaped or bar-shaped, but they are not limitedthereto. For example, but not by way of limitation, at least one of thefirst and second electrode cells 122 and 132, the first and secondconnecting parts 124 and 134, the first and second dummy patterns 126and 136 and the electrode parts 162 may be mesh shaped electrode orimplemented with mesh pattern. In other words, in another embodiment, atleast one of the sensing electrodes 120, the driving electrodes 130, thenoise detecting electrodes 160, the first and second dummy patterns 126and 136 may be implemented with mesh shape.

For example, but not by way of limitation, as shown in FIG. 6B, thefirst and second electrode cells 122 and 132, the first and secondconnecting parts 124 and 134, the first and second dummy patterns 126and 136, and the electrode parts 162 may be mesh shaped electrode orpattern that includes multiple conductive fine lines connected to oneanother to form a mesh shape. Also, in FIG. 6B, each of the connectionlines 164 is shown as a single line, but depending on embodiment, eachconnection line 164 may be implemented as mesh shape that includes aplurality of conductive fine lines connected to one another to form amesh shape (not shown). Also, in FIG. 6B, the conductive fine lines FLare shown to be arranged in a diagonal line direction, but thearrangement direction, shape, etc. of the conductive fine lines FL mayvary. Also, in FIG. 6B, for convenience, the contact hole (e.g., thefirst contact hole CH1 in FIG. 5) is omitted, but if the first electrodecells 122 and the first connecting parts 124 are arranged on differentlayers the first electrode cells 122 and the first connecting parts 124that form the sensing electrodes 120 may be physically and/orelectrically connected to each other via a contact hole that is notshown.

Meanwhile, in yet another embodiment, only a portion of the first andsecond electrode cells 122 and 132, the first and second connectingparts 124 and 134, the first and second dummy patterns 126 and 136, theelectrode parts 162 and the connection lines 164 may be board-shaped orbar-shaped electrode or pattern, and the remaining may be implemented asmesh-shaped. In other words, the sensing electrodes 120, the drivingelectrodes 130, the noise detecting electrodes 160, the first and seconddummy patterns 126 and 136 may have variable shapes or configurations.

In an embodiment, the electrode parts 162 may be connected in a firstdirection by the connection lines 164. One area of the connection lines164 may overlap the first electrode cells 122. In an embodiment, theelectrode parts 162 and the connection lines 164 may be provided as thesecond layer L2 of the sensor part 100 along with the first connectingparts 124. The electrode parts 162 and the connection lines 164 may beformed of a same material and connected in one body.

When the electrode parts 162 and the connection lines 164 are arrangedon the same layer as the first connecting parts 124, the connectionlines 164 may not overlap the first connecting parts 124. For example,but not by way of limitation, the connection lines 164 may electricallyconnect the adjacent electrode parts 162 so as not to contact the firstconnecting part 124. For example, the connection lines 164 detours anarea in which the first connecting parts 124 exist. As a result, thesensing electrode 120 and the noise detecting electrode 160corresponding to each other may maintain insulation from each other.

In an embodiment, an opening OP may be formed in each of the sensingelectrodes 120, and the electrode parts 162 of the noise detectingelectrodes 160 are arranged such that they are spaced apart from thesensing electrodes 120 in the openings OP. For example, but not by wayof limitation, in an embodiment, the opening OP may be formed insideeach first electrode cell 122, the first dummy patterns 126 may beprovided in the opening OP not to connected to the first electrode cell122, and at the same time, the electrode parts 162 of the noisedetecting electrodes 160 may be provided so as to overlap the firstdummy patterns 126. As a result, by reducing parasitic capacitance whichmay be formed between the noise detecting electrodes 160, the sensingelectrodes 120 and/or the driving electrodes 130, malfunction of thetouch sensor may be prevented, and the noise signal Sno may be moreeffectively detected.

FIGS. 9 to 12 show an embodiment relating to the sensor part shown inFIG. 4. Each of FIGS. 9 to 12 shows different modified embodiments withrespect to an embodiment shown in FIG. 5. In other words, FIGS. 5, 9 to12 show various embodiments relating to the sensor part shown in FIG. 4.In FIGS. 9 to 12, same reference numerals are used for similar or samecomponents as in the aforementioned embodiments, and detaileddescription thereof will be omitted.

Referring to FIG. 9, second and third dummy patterns 136 and 166overlapping each other are disposed inside the opening OP of each secondelectrode cell 132. In an embodiment, the second dummy pattern 136 maybe a floated island shaped pattern spaced apart from the secondelectrode cell 132 on the same layer as the second electrode cell 132.The third dummy pattern 166 may be provided on the same layer as theelectrode part 162 and the connection lines 164 that form the noisedetecting electrode 160. For example, but not by way of limitation, thethird dummy pattern 166 may be disposed to overlap the second dummypattern 136 with at least one insulating layer (e.g., the firstinsulating layer 170 shown in FIGS. 8A and 8B) interposed between thethird dummy pattern 166 and the second dummy pattern 136 and may bearranged on the lower part of the second dummy pattern 136 so as to bespaced apart from the second dummy pattern 136. In an embodiment, thethird dummy pattern 166 may be formed of the same material as theelectrode parts 162, but it is not limited thereto.

In an embodiment, the second dummy pattern 136 may have substantiallythe same or similar shape and size as the first dummy pattern 126, andthe third dummy pattern 166 may have substantially the same or similarshape or size as the electrode part 162. According to the embodimentshown in FIG. 9, patterns including the sensing electrode 120, thedriving electrode 130, the dummy patterns 126, 136 and 166 and theelectrode parts 162 in the active area 101 may have uniformconfiguration throughout the active area 101, thus more uniform viewing(or visual) characteristics may be secured throughout the active area101.

Referring to FIG. 10, the electrode parts 162 and the third dummypatterns 166 of the second layer L2 described in the above-mentionedembodiments may be omitted. In the embodiment in FIG. 10, the firstdummy patterns 126 provided as the first layer L1 along with the firstand second electrode cells 122 and 132 may be connected in the firstdirection via the connection lines 164 provided as the second layer L2.In other words, in the embodiment, the noise detecting electrode 160 maybe formed with the first dummy patterns 126 and the connection lines164. As such, depending on the embodiment, the first dummy patterns 126may be utilized as the electrode part of the noise detecting electrode160. The electrode parts (i.e., the first dummy patterns 126) may bespaced apart from the first electrode cells 122 and formed as the firstlayer L1 of the sensor part 100. The connection lines 164 may bedisposed as the first layer L1 to overlap the first electrode cells 122with at least one insulating layer, e.g., the first insulating layer170, interposed between the connection lines 164 and the first electrodecells 122. The connection lines 164 may be provided as the second layerL2 separated from the first layer L1, and may be electrically connectedto the electrode parts via a contact hole (not shown) formed through thefirst insulating layer 170.

Referring to FIG. 11, a pair of first dummy pattern 126 and electrodepart 162 overlapping each other may be electrically connected to eachother via at least one second contact hole CH2. For example, but not byway of limitation, the first dummy pattern 126 and the electrode part162 overlapping each other may be electrically connected via a pluralityof second contact holes CH2 formed through the first insulating layer170 interposed therebetween. Accordingly, the noise detecting electrode160 may be a multi-layer structure. In other words, in the embodiment,the first dummy patterns 126 may form each noise detecting electrode 160along with the electrode parts 162 and the connection lines 164.

Referring to FIG. 12, each of the first and second electrode cells 122and 132 may not include an opening OP described in the aforementionedembodiments. In the embodiment in FIG. 12, the first, second and thirddummy patterns 126, 136 and 166 that are described in the aforementionedembodiments may be omitted. The electrode parts 162 may be arrangedinside the first electrode cells 122 so as to overlap each one area ofthe first electrode cells 122, particularly the central part. Theelectrode parts 162 may be disposed to overlap the first electrode cells122 with at least a first insulating layer 170 interposed therebetweenand may be spaced apart from the first electrode cells 122. Accordingly,the sensing electrodes 120 and the noise detecting electrodes 160 maymaintain insulation from each other.

In the aforementioned embodiments, the sensor part 100 may include noisedetecting electrodes 160 distributed in the active area 101 in order todetect noise signal. In an embodiment, the structure, shape, etc. of thenoise detecting electrodes 160 may change.

FIGS. 13 and 14 show a touch sensor according to an embodiment. Forconvenience, FIG. 13 schematically shows the configuration of thesensing circuit with respect to a plurality of Rx channels, and FIG. 14shows the configuration of the sensing circuit with respect to the Rxchannel around one Rx channel in more detail. In other words, thesensing circuit with respect to the Rx channels shown in FIGS. 13 and 14may have substantially the same or similar structure. FIG. 15 showsanother embodiment of an analog-to-digital converter shown in FIGS. 13and 14. FIG. 16 shows another embodiment of a peak hold circuit shown inFIGS. 13 and 14. In FIGS. 13 to 16, same reference numerals are used forsimilar or same components as FIG. 4, and detailed description thereofwill be omitted.

Referring to FIGS. 13 and 14, as for the touch sensor in an embodiment,a plurality of noise detecting electrodes 160 may share one third wire146. In other words, in the embodiment, the plurality of noise detectingelectrodes 160 may be connected to one third wire 146 in common anddetect at once a noise signal Sno applied throughout the sensor part100. In an embodiment, the number of wires arranged inside the sensorpart 100 may be reduced. Therefore, the noise reduction structure in theembodiment may be useful for the narrow bezel type touch sensor as well.

Also, in an embodiment, the touch sensor may further include anamplifier circuit part 222 connected between the noise detectingelectrodes 160 and the signal receiving parts 221 and a peak holdcircuit 224 (PHC) (or a peak hold amplifier (PHA)) connected between thesignal receiving parts 221 and the analog-to-digital converter parts223. In an embodiment, the touch sensor may further include fifthswitches SW51 to SW54 for selectively connecting each signal receivingpart 221 and the peak hold circuit 224. In an embodiment, the touchsensor may further include sixth switches SW61 to SW64 and seventhswitches SW71 to SW74 for selectively connecting each analog-to-digitalconverter part 223 to the output terminal OUT of the correspondingsignal receiving part 221 or the output terminal of the peak holdcircuit 224.

In an embodiment, each signal receiving part 221 may include a firstinput terminal IN1 connected to the corresponding sensing electrode 120and a second input terminal IN2 connected to the noise detectingelectrodes 160 via the amplifier circuit part 222. Each signal receivingpart 221 may include a first amplifier AMP1 having first and secondinput terminals IN1 and IN2, a first switch SW1 and a second switch SW2connected in parallel between the output terminal OUT of the firstamplifier AMP1 and the first input terminal IN1, a first capacitor C1and a reset switch SWr connected in parallel between the output terminalOUT of the first amplifier AMP1 and the first switch SW1, and a secondcapacitor C2 and a first resistor R1 connected in parallel between theoutput terminal OUT of the first amplifier AMP1 and the second switchSW2. Each of the signal receiving parts 221 may output a voltage thatcorresponds to the voltage difference between the first input terminalIN1 and the second input terminal IN2.

In an embodiment, the first switch SW1 and the second switch SW2 may beturned on in different periods. For example, but not by way oflimitation, the first switch SW1 may be turned on in response to a firstmode during a period when the first mode is performed, and the secondswitch SW2 may be turned on in response to a second mode during a periodwhen the second mode is performed. In an embodiment, the first mode maybe a sensor driving mode (or normal mode) for detecting touch input, andthe second mode may be a gain calibration mode to calibrateamplification gain of the noise signal Sno per Rx channel in order tomaximize the noise offset effect.

In an embodiment, the amplifier circuit part 222 may be connectedbetween the noise detecting electrodes 160 and each second inputterminal IN2 of the signal receiving parts 221. The amplifier circuitpart 222 may receive the noise signal Sno from the noise detectingelectrodes 160, amplify it to correspond to a predetermined gain valueand output it to each signal receiving part 221.

For this, the amplifier circuit part 222 may include a second amplifierAMP2. In an embodiment, the second amplifier AMP2 may include a fifthinput terminal (or a fifth terminal) IN5 connected to the noisedetecting electrodes 160 via the third wire 146 and a sixth inputterminal (or a sixth terminal) IN6 connected to a bias power sourceVbias. In an embodiment, the fifth input terminal IN5 and the sixthinput terminal IN6 may be a non-inverting input terminal and aninverting input terminal, respectively, but they are not limitedthereto. In an embodiment, a second resistor R2 and a fourth capacitorC4 for stabilizing input may be connected in the fifth input terminalIN5. In an embodiment, the second resistor R2 and the fourth capacitorC4 may be connected in parallel between the fifth input terminal IN5 andthe bias power source Vbias. In an embodiment, at least one first bufferBU1 may be connected between the amplifier circuit part 222 and the biaspower source Vbias. In an embodiment, Ra and Rb in FIGS. 13 and 14 referto input/output impedance of the second amplifier AMP2.

The amplifier circuit part 222 may include a plurality of variableresistors VR1 to VR4 connected in parallel between the output terminalof the second amplifier AMP2 and the bias power source Vbias. In anembodiment, each variable resistor (one of VR1 to VR4) may be connectedto the second input terminal IN2 of the signal receiving part 221provided to each Rx channel via different output terminal (one of OUT1to OUT4) of the amplifier circuit part 222. In an embodiment, theresistance value of the variable resistors VR1 to VR4 may changecorresponding to the gain control signal GCS input from the processor225 via the seventh input terminal (or a seventh terminal) IN7. In theembodiment described above, a plurality of noise detecting electrodes160 may be connected to the fifth input terminal IN5 of the amplifiercircuit part 222 in common, but the second input terminal IN2 includedin signal receiving part 222 of each sensing electrodes 120 may beconnected to different variable resistors (one of VR1 to VR4) includedin the amplifier circuit part 222. The plurality of noise detectingelectrodes 160 may be connected to one third wire 146 to reduce thenumber of wires arranged in the sensor part 100, and the gain value ofthe noise signal Sno may be independently adjusted per Rx channel.Therefore, noise may be effectively offset per Rx channel.

In an embodiment, at least a third switch SW31 and SW32 may be providedbetween the second input terminal IN2 of each signal receiving part 221and the corresponding variable resistor (any one of VR1 to VR4) and/orbetween the second input terminal IN2 and the bias power source Vbias.However, in another embodiment, the third switch SW31 and SW32 may beomitted.

In an embodiment, each analog-to-digital converter part 223 may includea third input terminal (or a third terminal) IN3 connected to the outputterminal OUT of the signal receiving part 221 of the corresponding Rxchannel and a fourth input terminal (or a fourth terminal) IN4 connectedto the second input terminal IN2 of the signal receiving part 221. In anembodiment, at least one buffer BU21 to BU24 may be connected betweenthe second input terminal IN2 and the fourth input terminal IN4corresponding to each other.

In an embodiment, each analog-to-digital converter part 223 may beformed of a differential analog-to-digital converter outputting adigital signal corresponding to a voltage difference of the third andfourth input terminals IN3 and IN4 by operating in a differential mode.However, it is not limited thereto. For example, but not by way oflimitation, in another embodiment as shown in FIG. 15, theanalog-to-digital converter part 223′ may include a singled endedanalog-to-digital converter 2231. The analog-to-digital converter part223′ may include a fourth amplifier AMP4 having third and fourth inputterminals IN3 and IN4 (e.g., a differential amplifier) and a singledended analog-to-digital converter 2231 connected to the output terminalof the fourth amplifier AMP4. In FIG. 15, Rc to Rf show input/outputimpedance of the fourth amplifier AMP4.

In an embodiment, the third input terminal IN3 of each analog-to-digitalconverter part 223 or 223′ may be connected to a peak hold circuit 224via a sixth switch (one of SW61 to SW64). When the third input terminalIN3 is connected to the peak hold circuit 224, the third input terminalIN3 may be connected to the output terminal OUT of the correspondingsignal receiving part 221 via the peak hold circuit 224. Or the thirdinput terminal IN3 of each analog-to-digital converter part 223 or 223′may be directly connected to the output terminal OUT of thecorresponding signal receiving part 221 via a seventh switch (one ofSW71 to SW74). The analog-to-digital converter part 223 or 223′ mayoutput digital signal corresponding to a voltage difference of the thirdand fourth input terminals IN3 and IN4. For example, but not by way oflimitation, the analog-to-digital converter part 223 or 223′ may outputdigital signal having n bits (where n is a natural number) in responseto the voltage difference of the third and fourth input terminals IN3and IN4.

In an embodiment, the peak hold circuit 224 may be connected between theoutput terminal OUT of each signal receiving part 221 and the thirdinput terminal IN3 of the corresponding analog-to-digital converter part223 or 223′. In an embodiment, a plurality of signal receiving parts 221and/or the analog-to-digital converter parts 223 or 223′ may share onepeak hold circuit 224. For this, there may be fifth switches SW51 toSW54 for channel selection between the peak hold circuit 224 and thesignal receiving parts 221, and sixth switches SW61 to SW64 for channelselection between the peak hold circuit 224 and the analog-to-digitalconverter parts 223 or 223′.

In an embodiment, the peak hold circuit 224 may include a thirdamplifier AMP3, a first diode D1, a third capacitor C3 and a fourthswitch SW4. In an embodiment, the peak hold circuit 224 may furtherinclude at least one of the second diode D2, the third resistor R3 andthe third buffer BU3.

In an embodiment, the third amplifier AMP3 may include a seventh inputterminal IN7 and an eighth input terminal (or an eighth terminal) IN8.IN an embodiment, the seventh input terminal IN7 may be connected to theoutput terminal OUT of each signal receiving part 221 via the fifthswitch (one of SW51 to SW54). In an embodiment, the eighth inputterminal IN8 may be connected to the output terminal of the peak holdcircuit 224 (e.g., the output terminal of the third buffer BU3) via thethird resistor R3. In an embodiment, the third buffer BU3 may beconnected between the output terminal of the third amplifier AMP3 andthe third input terminal IN3 of the analog-to-digital converter parts223 or 223′.

In an embodiment, the first diode D1 may be connected between the outputterminal of the third amplifier AMP3 and the third buffer BU3. In anembodiment, the second diode D2 may be connected between the outputterminal of the third amplifier AMP3 and the eighth input terminal IN8.In an embodiment, the first and second diodes D1 and D2 may be connectedin the same direction. For example, but not by way of limitation, thefirst and second diodes D1 and D2 may be connected in a forwarddirection as shown in FIG. 14. However, the connection direction of thefirst and second diodes D1 and D2 may change. For example, but not byway of limitation, the first and second diodes D1 and D2 of the peakhold circuit 224′ may be connected in a reverse direction.

For example, but not by way of limitation, the peak hold circuit 224 maybe formed of a positive type peak hold circuit as shown in FIG. 14 or anegative type peak hold circuit as shown in FIG. 16. Since the peak holdcircuit 224′ in FIG. 16 may be the same as the peak hold circuit 224 inFIG. 14 except for the first and second diodes D1 and D2 being connectedin a reverse direction, the detailed description thereof will beomitted.

In an embodiment, the third capacitor C3 and the fourth switch SW4 maybe connected in parallel between a connection node N1 between the firstdiode D1 and the third buffer BU3 and the second input terminal IN2. Inan embodiment, the third capacitor C3 and the fourth switch SW4 may beconnected to the second input terminal IN2 via the second buffer BU2.Also, in an embodiment, if a plurality of signal receiving parts 221share one peak hold circuit 224 and 224′, the third capacitor C3 and thefourth switch SW4 may be connected to the second input terminal IN2 ofthe signal receiving part 221 provided to the corresponding Rx channelduring a period of calibrating the noise gain value with respect to eachRx channel. For this, a plurality of switches that are not shown may beconnected between the second input terminal IN2 of each signal receivingpart 221 and the peak hold circuit 224 and 224′.

Meanwhile, the configuration of the peak hold circuit 224 and 224′ isnot limited to the embodiment shown in FIGS. 14 and 16. For example, butnot by way of limitation, the peak hold circuit 224 and 224′ may beimplemented with the currently published, various types of peak holdcircuits (or peak hold amps).

In an embodiment, the touch sensor may be operated in a first mode and asecond mode. The processor 225 may operate differently in response tothe first mode and the second mode. For example, but not by way oflimitation, during when the first mode is performed, in response to thedigital signal input from each analog-to-digital converter part 223 or223′, the touch input occurring in the sensor part 100 may be detected.Also, while the second mode is being performed, the processor 225 mayoutput a gain control signal GCS for calibrating the gain value of theamplifier circuit part 222 in response to the digital signal input fromeach analog-to-digital converter part 223 or 223′. For example, but notby way of limitation, the processor 225 may output a gain control signalGCS which calibrates the gain value of each variable resistor VR1 to VR4to offset the noise as much as possible in each signal receiving part221 with respect to each Rx channel.

In other words, the gain control signal GCS may be a control signal forcalibrating the gain value of the amplifier circuit part 222 so as tomake the magnitude of the noise included in the input signal receivedvia two input terminals (first and second input terminals IN1 and IN2)of the signal receiving part 221 substantially the same or similarwithin a predetermined error range. That is, while the second mode isbeing performed, by optimizing the gain value of the amplifier circuitpart 222, the noise signal Sno flown into the first and second inputterminals IN1 and IN2 of the signal receiving part 221 during the periodwhen the first mode is being performed may be effectively offset.Consequently, SNR of the touch sensor may be increased, and sensitivitymay be enhanced.

In an embodiment, when the touch sensor is driven in a first mode, byinputting a noise signal Sno into a reference terminal of each signalreceiving part 221, e.g., the second input terminal IN2, the noise maybe offset. In an embodiment, by independently calibrating the gain ofthe noise signal Sno per Rx channel, the noise may be more effectivelyoffset.

Noise signals Sno having different magnitudes (or levels) may be flowninto the sensing electrodes 120 depending on the locations of thesensing electrodes 120. Therefore, in an embodiment, the gain value ofthe noise signal Sno input into each signal receiving part 221 may beindependently calibrated depending on the magnitude of the noise signalSno that is flown into each Rx channel. For example, but not by way oflimitation, while the second mode is being performed, each resistancevalue of the variable resistors (VR1 to VR4) may be calibrated in orderfor noise to be offset as much as possible per Rx channel using the gaincontrol signal GCS. In other words, while the second mode is performed,the resistance values of the variable resistors (VR1 to VR4) may beautomatically calibrated (or adjusted) so that the noise signal Sno maybe offset (or canceled) as much as possible in each signal receivingpart 221 during the first mode to be succeeded. Consequently, while thefirst mode is performed which detects actual touch input, noisecomponents included in the sensing signal Sse1 input to each Rx channelmay be more accurately matched and offset.

Accordingly, in an embodiment, by effectively offsetting common modenoise flown into the sensor part 100 of the touch sensor, the SNR of thetouch sensor may be increased. Consequently, malfunction of the touchsensor according to the noise signal Sno may be minimized, and thesensitivity may be enhanced.

FIG. 17 shows operation of a touch sensor in a first mode according toan embodiment. FIG. 18 shows operation of a touch sensor in a first modein another embodiment. FIG. 18 shows the analog-to-digital converterbeing formed as shown in FIG. 15, and the remaining operation processesare substantially the same as the embodiment in FIG. 17.

FIGS. 17 and 18 are simple drawings of the differential circuit when thetouch sensor is operating in the first mode in the embodiment in FIGS.13 to 16, and thus the drawings of the buffer, etc. are omitted. Forconvenience, operations of the first mode of the touch sensor based onone Rx channel (e.g., the last Rx channel) as shown in FIGS. 14 and 15will be described.

Referring to FIGS. 17 and 18, in an embodiment, when the touch sensor isoperating in the first mode, the first switch SW1, the third switch SW31connected between the second input terminal IN2 of the corresponding Rxchannel and the variable resistor VR4, and a seventh switch SW74connected between the signal receiving part 221 of the corresponding Rxchannel and the analog-to-digital converter part 223 or 223′, among theswitches shown in FIGS. 14 and 15, may be turned on. In an embodiment,the remaining switches may be turned off. Consequently, a differentialcircuit as shown in FIGS. 17 and 18 may be formed.

In an embodiment, the first mode may be performed during a regular modeperiod (e.g., the time a user actually uses the touch sensor or thedisplay device) when the touch sensor is activated. During the periodwhen the first mode is performed, the driving circuit 210 maysequentially supply driving signal Sdr to the driving electrodes 130.Accordingly, the sensing signal Sse1 corresponding to the driving signalSdr from the corresponding sensing electrode 120 may be input into thefirst input terminal IN1 of the signal receiving part 221, and the noisesignal Sno from the noise detecting electrodes 160 may be input into thesecond input terminal IN2 via the amplifier circuit part 222. Theamplifier circuit part 222 may amplify the noise signal so as tocorrespond to the magnitude of the noise component included in thesensing signal Sse1 and output it. The signal receiving part 221 mayoutput signal corresponding to voltage difference between the first andsecond input terminals IN1 and IN2. The signal receiving part 221 mayoutput a signal corresponding to a voltage difference of the first andsecond input terminals IN1 and IN2. Meanwhile, the reset switch SWr maybe turned on about the time when the integrator (for example, but not byway of limitation, the integrator formed of the first amplifier AMP1 andthe first capacitor C1), formed inside of the signal receiving part 221and equivalently formed, is reset.

The analog-to-digital converter part 223 or 223′ may output a digitalsignal corresponding to the voltage difference of the output node OUT ofthe signal receiving part 221 and the second input terminal IN2 based onthe potential of the second input terminal IN2. The processor 225 mayreceive a digital signal from the analog-to-digital converter part 223or 223′ and detect touch input in response to the digital signal.

In an embodiment, when the touch sensor operates in the first mode,touch input may be detected in response to the voltage differencebetween the sensing signal Sse1 input to the first input terminal IN1and the input the noise signal Sno (a noise signal that is amplifiedaccording to a predetermined gain value) input to the second inputterminal IN2. In other words, the sensing circuit 220 may detect thesensing signal Sse1 by having the potential of the noise signal Snoinput to the second input terminal IN2 as the reference potential, anddetect touch input in response. In an embodiment, by effectivelyoffsetting the noise signal Sno flown into the sensor part 100, thesensitivity of the touch sensor may be enhanced.

FIG. 19 shows operation of a touch sensor in a second mode according toan embodiment. FIG. 20 shows operation of a touch sensor in a secondmode in another embodiment. FIG. 20 shows the analog-to-digitalconverter being configured as in the embodiment shown in FIG. 15, andthe rest of the operation process are substantially the same as theembodiment in FIG. 19. Meanwhile, FIGS. 19 and 20 show the embodimentwhere the peak detection circuit detects the forward-direction peakvalue of the signal output from the signal receiving part, but it is notlimited thereto. For example, but not by way of limitation, if the peakdetection circuit is configured as shown in FIG. 16, the peak detectioncircuit may detect the reverse direction peak value of the signal outputfrom the signal receiving part.

FIGS. 19 and 20 show the differential circuit in a simplified mannerwhen the touch sensor operates in a second mode according to theembodiments in FIGS. 13 to 16, and buffer, etc. are omitted. Forconvenience, based on one Rx channel (e.g., the last Rx channel) shownin FIGS. 14 and 15, the operation of the second mode of the touch sensoris described.

Referring to FIGS. 19 and 20, in an embodiment, when the touch sensoroperates in a second mode, the second switch SW2, and the third switchSW31 connected between the second input terminal IN2 of thecorresponding Rx channel and the variable resistor VR4, the fifth switchSW54 connected between the peak hold circuit 224 and 224′ and the signalreceiving part 221 of the corresponding Rx channel and the sixth switchSW64 connected between the peak hold circuit 224 and 224′ and thecorresponding analog-to-digital converter part 223 or 223′ may be turnedon. The rest of the switches may be turned off. As such, thedifferential circuit such as the one shown in FIGS. 19 and 20 may beformed.

In an embodiment, the second mode may be, per Rx channel, a gaincalibration mode for calibrating the amplification gain of the noisesignal Sno2 to be input to the second input terminal IN2. In anembodiment, the second mode may be performed at least once in a moduleprocess prior to shipment of the product (the touch sensor and/or thedisplay device including the touch sensor according to the embodiment).In an embodiment, the second mode may be performed at a predeterminedtime (e.g., at the power-on time of the touch sensor) and/or during apredetermined period even after the product has been shipped.

In an embodiment, during the period when the second mode is performed,the driving circuit 210 may not supply a driving signal Sdr to thedriving electrodes 130. Meanwhile, during the period when the secondmode is performed, the display driver (400 in FIG. 1) may drive thedisplay panel 300 for the display panel (300 in FIG. 1) to display apredetermined image. Accordingly, while the second mode is performed, acommon mode noise (display noise) may be flown into the sensor part 100from the display panel 300, etc.

While the second mode is performed, the first and second noise signalsSno1 and Snot may be input from the sensing electrode 120 and the noisedetecting electrode 160 to the first and second input terminals IN1 andIN2, respectively, of the signal receiving part 221. An amplified noisesignal Sno2 may be input according to the gain value of the amplifiercircuit part 222 to the second input terminal IN2. As such, while thesecond mode is performed, the signal receiving part 221 may operate as atrans-impedance amplifier. When the first and second noise signals Sno1and Sno2 that have the same magnitude are input to the first and secondinput terminals IN1 and IN2, respectively, common mode noise may beoffset.

While the second mode is performed, the peak hold circuit 224 may detecta positive peak value (or, a negative peak value, or the sum of thepositive peak value and the negative peak value) of the signal output tothe output terminal OUT of the signal receiving part 221 and output itto the third input terminal IN3 of the analog-to-digital converter part223 or 223′. That is, the peak hold circuit 224 may detect the magnitudeof the signal output from the output terminal OUT of the signalreceiving part 221 (the magnitude of the noise corresponding to thevoltage difference of the first and second noise signals Sno1 and Sno2).

The analog-to-digital converter part 223 or 223′ may output a digitalsignal corresponding to the magnitude of the noise input from the peakhold circuit 224 based on the potential of the second input terminalIN2. The processor 225 may generate a gain control signal GCS forcalibrating the gain value of the second noise signal Sno2 such that themagnitude of the noise may reduce in response to the digital signalinput from the analog-to-digital converter part 223 or 223′ and mayoutput it to the amplifier circuit part 222. As such, the processor 225may calibrate the resistance value of the variable resistor (e.g., VR4)connected between the second input terminal IN2 of the corresponding Rxchannel and the noise detecting electrode 160 using the gain controlsignal GCS. For example, but not by way of limitation, the processor 225may calibrate the amplifying gain of the second noise signal Sno2 bycalibrating the resistance value of the variable resistor (e.g., VR4)using the gain control signal GCS until the voltage difference of thefirst and second noise signals Sno1 and Sno2 (e.g., the magnitude of thepeak value detected from the peak hold circuit 224) input to the firstand second input terminals IN1 and IN2 becomes substantively “0” or isminimized to “0”. Accordingly, the resistance value of the variableresistor (VR1 to VR4) of the amplifier circuit part 222 with respect toeach Rx channel may be set to offset the noise as much as possible.

In the aforementioned embodiment, while the second mode is performed, again control signal GCS may occur in order to reduce or minimize thevoltage difference of the first and second noise signals Sno1 and Sno2in response to the voltage difference of the first and second noisesignals Sno1 and Sno2 input to the first and second input terminals IN1and IN2, respectively. The resistance value of the variable resistor(VR1 to VR4) (the gain value of the amplifier circuit part 222 withrespect to each Rx channel) may be calibrated using the gain controlsignal GCS. Consequently, the noise signal Sno flown into the sensorpart 100 may be more accurately offset during the ensuing first modeperiod.

FIG. 21 shows a touch sensor and operation of the touch sensor in asecond mode according to yet another embodiment. With reference to FIG.21, detailed description of the similar or same components as found inthe aforementioned embodiments will be omitted.

Referring to FIG. 21, the peak hold circuit 224 and 224′ disclosed inthe aforementioned embodiments may be omitted. The analog-to-digitalconverter part 223 or 223′ may generate a digital signal correspondingto the instant magnitude of the analog signal output from the signalreceiving part 221 by sampling at high speed the analog signal which isoutput from the signal receiving part 221. The processor 225 may detectthe peak value (magnitude) of the analog signal output from the signalreceiving part 221 in response to the digital signal. The processor 225may generate a gain control signal GCS based on the peak value of thedetected analog signal, and calibrate the gain value of the amplifiercircuit part 222 using the gain control signal GCS.

By way of summary, common mode noise that is introduced into the sensorpart of the touch sensor may be effectively offset. Accordingly, thetouch sensor's malfunctioning as a result of noise signal may beminimized, and the sensing sensitivity of the touch sensor may beimproved.

While the spirit and scope of the inventive concept describe in detailexemplary embodiments of the inventive concept, it should be noted thatthe above-described embodiments are merely descriptive and should not beconsidered as limiting. Further, it should be understood by thoseskilled in the art that various changes, substitutions, and alterationsmay be made herein without departing from the scope of the inventiveconcept as defined by the following claims.

What is claimed is:
 1. A sensor-display panel, comprising: a displaypanel comprising pixels and an encapsulation layer; a first electrodeformed in a mesh pattern, the first electrode comprising first electrodecells arranged along a first direction and at least one first conductivepattern provided between the first electrode cells, each of the firstelectrode cells having an opening; a second electrode spaced apart fromthe first electrode, the second electrode comprising electrode partseach disposed in the opening of one of the first electrode cells in aplan view of the sensor-display panel, and at least one secondconductive pattern provided between the electrode parts; a thirdelectrode spaced apart from the first and second electrodes and formedin a mesh pattern, the third electrode comprising second electrode cellsarranged along a second direction and at least one third conductivepattern provided between the second electrode cells; and a driving unitconnected to the first, second and third electrodes through differentterminals and operating in a first mode or a second mode, the drivingunit configured to supply a driving signal to the third electrode and toreceive sensing signals from the first and second electrodes whenoperating in the first mode, wherein the first, second and thirdelectrodes are formed on the encapsulation layer, and wherein the secondconductive pattern and at least one of the first and third conductivepatterns are on a layer different from the first and second electrodecells.
 2. The sensor-display panel of claim 1, wherein the secondelectrode is formed in a mesh pattern.
 3. The sensor-display panel ofclaim 1, wherein the second conductive pattern connects the electrodeparts to each other along the first direction and is spaced from thefirst conductive pattern in the plan view of the sensor-display panel.4. The sensor-display panel of claim 3, wherein: the first electrodecells are on a first layer on the encapsulation layer, and the secondconductive pattern and at least one of the first and third conductivepatterns are on a second layer between the encapsulation layer and thefirst layer.
 5. The sensor-display panel of claim 1, wherein the drivingunit is configured to detect an input corresponding to a voltagedifference between the sensing signals output from the first and secondelectrodes when operating in the first mode.
 6. The sensor-display panelof claim 1, wherein the driving unit is configured to adjust a gainvalue for amplifying a noise signal from the second electrode, usingvalues of the sensing signals from the first and second electrodes, whenoperating in the second mode.
 7. The sensor-display panel of claim 6,wherein the driving unit is configured to adjust the gain value so thata voltage difference between the sensing signals output from the firstand second electrodes is reduced when operating in the second mode. 8.The sensor-display panel of claim 6, wherein the driving unit comprises:a sensing circuit connected to the first and second electrodes; and adriving circuit connected to the third electrode.
 9. The sensor-displaypanel of claim 8, wherein the sensing circuit comprises: a signalreceiver comprising a first terminal connected to the first electrodeand a second terminal connected to the second electrode; an amplifiercircuit connected between the second terminal and the second electrode,the amplifier circuit configured to amplify the noise signal receivedfrom the second electrode in accordance to the gain value; ananalog-to-digital converter comprising a third terminal connected to anoutput terminal of the signal receiver and a fourth terminal connectedto the second terminal, the analog-to-digital converter configured tooutput a digital signal corresponding to a voltage difference betweenthe third and fourth terminals; and a processor configured to detect aninput in response to the digital signal during the first mode, and tooutput a gain control signal for calibrating the gain value during thesecond mode.
 10. The sensor-display panel of claim 9, wherein the signalreceiver comprises: a first amplifier including the first and secondterminals; a first switch turned on during the first mode and a secondswitch turned on during the second mode, the first and second switchesbeing connected in parallel between the first terminal and an outputterminal of the first amplifier; a first capacitor and a reset switchconnected in parallel between the first switch and the output terminalof the first amplifier; and a second capacitor and a first resistorconnected in parallel between the second switch and the output terminalof the first amplifier.
 11. The sensor-display panel of claim 9, whereinthe amplifier circuit comprises: a second amplifier including a fifthterminal connected to the second electrode and a sixth terminalconnected to a bias power source; and a variable resistor connectedbetween an output terminal of the second amplifier and the bias powersource and having a resistance value changing in response to the gaincontrol signal.
 12. The sensor-display panel of claim 11, wherein thesecond terminal is connected to the variable resistor.
 13. Thesensor-display panel of claim 9, wherein the sensing circuit furthercomprises a peak hold circuit connected between the output terminal ofthe signal receiver and the third terminal.
 14. The sensor-display panelof claim 13, further comprising: at least one switch connected betweenthe peak hold circuit and the third terminal; and at least one switchconnected between the output terminal of the signal receiver and thepeak hold circuit.
 15. The sensor-display panel of claim 1, wherein thedriving unit is configured to stop supplying the driving signal to thethird electrode during the second mode.
 16. The sensor-display panel ofclaim 1, comprising: a plurality of first electrodes including the firstelectrode, the plurality of first electrodes sequentially arranged inthe second direction and respectively extending in the first direction;and a plurality of second electrodes including the second electrode, theplurality of second electrodes sequentially arranged in the seconddirection and respectively extending in the first direction.
 17. Thesensor-display panel of claim 16, wherein: the driving unit comprises aplurality of signal receivers; and each of the plurality of firstelectrodes is connected to a different one of the plurality of signalreceivers.
 18. The sensor-display panel of claim 17, further comprisinga wire commonly connected between the plurality of second electrodes andthe driving unit.
 19. The sensor-display panel of claim 16, furthercomprising: a plurality of third electrodes including the thirdelectrode, the plurality of third electrodes sequentially arranged inthe first direction and respectively extending in the second direction.20. The sensor-display panel of claim 1, wherein the first and thirdelectrodes constitute a sensor part of a capacitive touch sensor. 21.The sensor-display panel of claim 1, wherein: the first conductivepattern connects the first electrode cells to each other along the firstdirection; and the third conductive pattern connects the secondelectrode cells to each other along the second direction.
 22. Thesensor-display panel of claim 1, wherein: the first conductive patternextends in the first direction; the second conductive pattern extends inthe first direction; and the third conductive pattern extends in thesecond direction.